Labour could try to block Heathrow third runway in the Commons

Labour could vote against plans for a third runway at Heathrow airport in a move that could see the decades-long plan blocked by Parliament.

Senior allies of Jeremy Corbyn told the Financial Times that he and colleagues are almost certain to oppose the third runway in a Commons vote on environmental grounds.

The move means the plans for the £16.5billion runway are at significant risk because as many as 60 Tory MPs are opposed to the expansion of Heathrow.

It could leave Theresa May, the Prime minister, dependent on the support of the Scottish National Party and rebel MPs as she tries to push the plans through Parliament.

Boris Johnson, the Foreign Secretary, and Justine Greening, the Education Secretary, have been given a free vote on the issue. The vote is expected to take place in the first half of next year.

John McDonnell, the Shadow Chancellor, is a vociferous opponent of the scheme. One senior Labour figure told the Financial Times: “It has to pass our tests and no one here expects that to be likely."

Another senior Labour figure said: “If the vote is any time soon there is no way we would back it, mainly on the basis of air quality, and that’s unlikely to change any time soon.”

Labour's manifesto said that the party would need to be satisfied that certain environmental conditions were being met if it was to give it's backing to Heathrow. The manifesto said that noise and air quality issues would have to be met, along with the UK's climate change obligations.